Question

Important characteristics of cyclostomata

Answer 1

Hey there...
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Find ur answer below!!

• CYCLOSTOMATA:

¤General characters :

- Cranium and vertebral column is present ,but jaws are absent...
( cartilanegenous endoskeleton)

- Notochord is also persistent.

- Long elongated body.

- Suctorial, funnel like circular mouth, without jaws.

- Single nostril .( monorhynous condition)

- Third eye ( pineal eye) is present .

- Known as 'false fishes'... As paired fins.. Scales and jaws are absent.

¤ Digestive system :

- Spiral thyplosole is present which helps in increasing surface area.

- Alimentary canal is complete.. Both mouth and Anus is present.

- Stomach is absent .

¤ Blood vascular system :

- closed
- heart is two chambered.
-rbcs are nucleated.

¤ Excretion :

- Takes place through mesonephric or pronephric kidney.

¤ Respiration :

- 6-15 Paired gill slits are found which helps In respiration.

¤ Hearing mechanism :

- Only internal ear is present consisting of one or two semicircular canals for balancing.

¤ Reproduction :

- These organisms are unisexual.

- Fertilisation is external.

- Development is indirect ..posseses larval stage called "Ammocoete "


• These organisms are marine.. And migrate to freshwater for spawning.. After spawning.. They die and their Larva after metamorphosis return back to sea..

- EG.:
•Petromyzon..(Lamprey) -exhibits anadromous migration.

•Myxine (hag fish)



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# hope it helps!!

Answer 2

Answer:

Cyclostomata

1. Their body is round and elongated like an eel.

2. Their heart is two chambered.

3. All members of cyclostomata are ectoprarasites.

4. Respiration is through gill.

5. Their circulation is closed type.

6. Notochord is present through out their life.

7. development may be direct or indirect.

8.example - petromyzon and myxine.